The invention relates to a method for producing perfect-bound book blocks for books or similar printed products with the aid of a perfect binding apparatus, provided with clamps arranged at a distance to each other and driven successively along a circular path. The loose book blocks, composed of gathered printed sheets, that are positioned transverse to the conveying direction inside uniformly spaced-apart conveying units on a transfer region are supplied to these clamps once the conveying units reach the transfer region, or before the conveying units reach the transfer region, below the circular path for the perfect binding apparatus and are then clamped into the clamps with the spines facing downward, such that they can be transported while positioned upright for the further processing in the perfect binding apparatus.
Perfect binding methods are disclosed for producing magazines, books, paperback books, catalogs or similar printed products. For this, individual printed sheets are initially gathered in a specific sequence into loose book blocks and are subsequently transported to a perfect binding apparatus for processing the spine region of the printed sheets, applying adhesive and gluing a cover onto the spine. In a final step, the unfinished, bound printed product is normally trimmed precisely along the remaining three side edges to obtain the finished dimensions.
According to a first method disclosed in the prior art, the printed sheets are collected inside a conveying channel of a gathering machine, wherein the spines of the printed sheets are aligned parallel to the conveying direction and, maintaining this alignment, are moved past the processing stations of a perfect binding apparatus while held by clamps driven to circulate along a circular path, wherein the printed sheets are processed in these stations and are provided with a cover. This alignment of the spines parallel to the conveying direction results in an easy transfer of the printed sheets to the perfect binding apparatus and also makes it possible to use a simple design for the processing stations of the perfect binding apparatus. The maximum possible production speed limit in this case is determined by the maximum possible conveying speed inside the gathering channel of the gathering machine, which can still be used without causing flow turbulences to lift lightweight printed sheets off the underneath positioned stack. A gathering machine of this type is described in further detail in the European patent document 1 520 817 A1.
The European patent document 0 675 005 B1 describes a perfect binding apparatus for which the holding components are oriented transverse to the circulation direction and are driven continuously, wherein a printed product can be inserted at the feeding location into each holding component that is passing by. These processing stations are designed to act upon each printed product passing by and are provided with processing tools which at least in some sections travel along with the printed products in circulating direction to process these products while they move along. The production capacity can be increased owing to the fact that the printed sheets are conveyed and transferred with the spines being oriented transverse to the conveying direction. However, the manufacture of the processing stations that move along is extremely involved and expensive and the processing stations are susceptible to malfunctions during the operation.
According to a different approach, disclosed in the European patent document 1 886 832 A1, the printed sheets are collected on stacking tables with the spines aligned transverse to the conveying direction, are subsequently accelerated, are rotated by 90° and then transferred while moving in longitudinal direction to a perfect binding apparatus also moving in longitudinal direction. An increase in the capacity is possible with this method, however the required number of complex configured stacking tables and long transfer region between the collection region and the perfect binding apparatus are disadvantageous.
According to a different reference, European patent document 1 886 833 A1, the printed sheets are gathered on stacking tables with the spines aligned transverse to the conveying direction, are subsequently accelerated, are rotated by 90°, are gripped by grippers attached to a traction device while moving in longitudinal direction, and are then transferred to a perfect binding apparatus moving in longitudinal direction. A production increase is also possible with this method, however the required complex design of the transfer region and the distance between the gathering region and the perfect binding apparatus are disadvantageous.